4E WAS Wizards of the Coast's attempt to bring new players into the market. Lets look at all the things they did:
Removed finicky systems, subsystems, sub-subsystems, corner cases, walls of text, etc.
Every class played right out of the box. Yes, more classes added more variety, new material added new stuff you could do, but you could make a Fighter using PHB 1 and you'd be just fine.
We're playing in a fantasy game!
World of Warcraft, Everquest, Final Fantasy, etc. People have come to expect fantastic settings to have fantastic races. DnD's races... lacked. Flip open the PHB and you have: humans, humans with pointy ears, short humans, short humans take 2, short humans take 3 (with beards) and half-orcs (who are humans with little tusks).
Yeah, gently caress that noise. You can play a Dragon! A half-demon! Their mystic elves had all black eyes and could teleport through the feywild!
We're big damn HEROES!
You ever see Cloud stop to rest for 2 weeks because of a few injuries? Does your character in WoW stop to rest? Does any of your fantasy heroes ever die to a goblin arrow? No!
4E was goddamn HEROIC. Level 1? Okay. You're just starting out and guess what? You kick ass and take names. And it's only getting better from here.
Powers
You want to know what turns off players of other games from PnP rpgs? Endless table lookup. Rules arguments. Wondering how things work.
Powers are self-contained. They do exactly what they say. No "I get 4 level 1 spell slots? What can I do with those?" Nope. You have powers. You use them.
Game systems
You like boss fights? Why can't DnD do boss fights? You dislike measuring in 5 ft increments (or live in ANY OTHER COUNTRY THAN THE US)? Here, spaces. Neutral towards metric/english, perfectly comprehensible, and diagonals measure easily. You want to defend people? You can defend people (and in a much more interesting manner than traditional 'aggro' mechanics). You play video games? Good on you. DnD 4E can do anything your video game can do, do it cooler, do it more interesting, and screw the stupid grinding everyone hates.
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Here we are now, people. Don't start whining WotC doesn't do enough to bring in new players when you can click over to Penny Arcade and SEE how DnD 4E did everything you wanted to happen with their edition. And you killed it.